1. Field of the Invention
The present invention relates to a steam oven provided on an aircraft.
2. Description of the Related Art
Japanese Patent Application Laid-Open Nos. 2010-210118 and 2006-69457 disclose a state of providing the steam oven for an aircraft on a galley and a water leakage prevention device.
Conventionally, software used in a controller of the steam oven for an aircraft is monitored and protected by a watchdog timer as in a general electronic device. It is supposed that the watchdog timer cannot be cleared within a certain time when a CPU controlled by the software does not normally act for some reasons, and there is a method of forcibly resetting the CPU after a certain time to solve an abnormal state of the software when the watchdog timer is not cleared.
However, the method does not solve a fundamental problem of the software and this is merely temporal solution, so that the problem might occur again. Also, when design of the software is not appropriate, a phenomenon in which abnormality occurs in a part of the software even though the watchdog timer functions occur. Therefore, it is said that mounting of the watchdog timer does not completely solve the abnormality of the software.
When the software is used to control a solenoid valve (hereinafter, referred to as a valve) for steam of the steam oven (hereinafter, referred to as an oven) used in the galley of an aircraft, it is predicted that the valve is abnormally released and an inside of the oven is filled with water for the steam, and further the water overflows under floor by defect of the software itself and runaway of the CPU occurred by failure of hardware. Since an electronic device is stored under floor of the aircraft, water leakage in large quantity is dangerous and measures against this are required.